An Unlikely Intruder
by Spartangal22
Summary: With Sherlock recuperating in the hospital, and John refusing to see her, Mary pays a visit to a most unexpected person. There are a few things she needs to know.


"How long have you known?"

Mycroft glanced up from his newspaper. There was nothing particularly exciting to read about today. Talk shows were busy gossiping about the latest news regarding a certain royal cousin's romance, but he'd been monitoring that situation for weeks. World leaders were gathering shortly to discuss the ongoing crisis in the Middle East, but they would be discussing reports that he had proofread two nights earlier, and he had no interest in reading press releases analyzing his own words.

Sometimes it was so dull, knowing everything before the rest of the world. Understanding so much more than everyone else.

The newspaper was more a façade to prevent anyone from actually speaking to him. The flimsy pieces of paper provided a surprisingly efficient barrier from the rest of civilized society. It made him appear to be investing himself in the world around him, concentrating on something more than himself, and people seemed to respect that. Why, he had no idea.

He wasn't even reading the words swimming before his eyes today. His mind was swimming with thoughts, none of which had anything to do with the most recent football scores. No, today his brain was reserved for its most challenging, and frequent, trouble: his little brother, who had only recently been picked up from a drug den, gotten himself shot, escaped from hospital, and then returned with internal hemorrhaging. If Mycroft had the energy to sigh, he would have.

And then, when he wasn't receiving calls from John Watson or the hospital or Scotland Yard, he was receiving them from his parents. That, he could also blame on Sherlock. As if he were responsible for the man's every fault, of which there were a great many recently.

But the voice interrupting his reading today was not that of a disgruntled detective, or angry friend, worried parent, or annoying brother. Actually, Mycroft realized, setting his paper aside, this was the true voice of his troubles, the one responsible for the parental phone calls and the hospital and the shot.

"Mary," he said. "To what do I owe the pleasure?"

"Oh, cut the niceties, Mycroft," Mary snapped, presumptuously pulling up a seat and sitting down across from him. "How long have you known?"

Mycroft pressed his lips together, trying to ignore the mark she'd left on the floor from the chair's legs. "That depends. Are you asking me how long I've known that you shot my little brother? Or how long have I known that Mary Morstan was an alias? Or perhaps you were wondering how long I have known about who you were…before?"

When Mary's face remained stoic, Mycroft continued. "The answer to the first is, of course, as soon as I heard news of the shooting, which was when you telephoned the police. Thank you for that," he added, not entirely sincere, but not as sarcastic as he could have been. "That ties into the second question because I wouldn't have identified you as the shooter had I truly believed you to be the sweet nurse you portrayed. I knew the truth about Mary Morstan much sooner than Sherlock did. As to the third-"

"You didn't say when," Mary interrupted. She pushed aside a stray lock of hair - he knew why she kept it short - and studied him. "Was it before the wedding? Or after?"

"Ages before." Mycroft raised an eyebrow. "You know this. When you approached your marks, how much research did you do ahead of time?"

"I'm your mark now, am I?" She seemed amused at the idea, but Mycroft shook his head.

"I studied you no more than I study anyone in my brother's life. What I found was that there wasn't much to study, but I hardly believed that for a second."

"Why is that?"

"Because John Watson had taken an interest in you and John has a tendency towards rather…more interesting people than most, shall I say."

Rather than be annoyed at being found out, or offended at his remarks towards her husband, Mary grew more curious with his words. She leaned forward, smiling. "So there wasn't anything about me that gave me away, then?"

Mycroft nodded, conceding that point. "Yes, you did an excellent job of covering your tracks. Birth certificate, college degrees, even childhood friends and photographs. You did a fantastically thorough job of creating a history for yourself. There was nothing suspicious about it, to the average mind."

"Which eliminates yourself, I suppose."

Mycroft frowned at the playfulness in her tone. "Yes, it does."

She scooted her chair closer, smiling. "How did you do it, then? Track me?"

Mycroft instinctively moved his own chair a little back. "I didn't track you; rather, I tracked Mary Morstan. The _real_ woman. Once it became clear that you'd stolen her identity, it was much easier to find the real _you._ "

"Oh?" She asked, eager. "How so?"

"Facial recognition software. You've traveled quite a bit."

"All under different names," she pointed out quickly.

"Yes. I made a chronology of your many lives for the better part of an afternoon until you disappeared entirely. I suppose that was when you first changed your identify from L-"

"Yes, alright," she snapped, her voice sharp for the first time that night.

Mycroft smirked. "I'm only answering your question, Mrs. Watson," he said pointedly. "Or are you done with that one now too?"

Mary glared. "I suppose you know everything that happened under those names too, then." It wasn't a question so Mycroft didn't answer. "Why keep my secret this long? Why protect me?"

"I wasn't protecting you at all," Mycroft retorted. "Quite the opposite, in fact. I saw no disadvantage to having a person with your…skillset at my brother's side. So long as you were with us."

"I shot him." The admission took Mycroft by surprise, though it shouldn't have. He'd already pointed that out this very evening. Perhaps it was the blunt way she had said it, a tone he was more familiar with coming from himself or his brother. Or perhaps it was the way her face didn't match her voice at all, what with the undeniable traces of guilt etched into the bags beneath her eyes.

He cleared his throat. "I'm well aware of that."

"So why keep the secret?" She pressed. "I _shot_ him."

Mycroft sighed. He plucked his umbrella from where it leaned up against his chair and held it in front of him, staring hard at Mary. He took a deep breath, and spoke slowly. She was smart, but still. "Your loyalties lie first with John Watson, then with my brother. Mine lie first with my brother, then England, and John Watson falls somewhere after that. If it came down to protecting my brother or protecting your husband, I would chose the former even if it meant hurting the latter. That does not mean that I harbor any ill wishes towards John; I simply have a duty to my brother. I suppose that scenario is not much different from the one you faced in Magnussen's office."

Mary blinked, sitting back in her chair. "I suppose that about sums it up." She paused for a second, then added dryly, "You mind explaining that to my husband for me?"

"Yes, I would mind." Mycroft turned the umbrella over in his hands. "I harbor no ill wishes towards you either, Mary. There are moments where I would like very much to shoot my brother as well, though I don't think either of us should make a habit of it."

Mary almost laughed then, and Mycroft felt inexplicably pleased with himself. He frowned, forcing that feeling away forever.

"Moving on to the real reason you are here," he said, and Mary raised an eyebrow. "I have no plans of revealing your past. Nor do I plan to hold that over you each time we meet, which I imagine will be unavoidable given the strange relationship between my brother and your husband."

"You did manage to avoid my wedding."

"A small mercy for all of us," he said, then continued on as if she hadn't interrupted. "You have no reason to fear me."

Mary did laugh then. "Oh, I'm not afraid of you, Mycroft."

"You might want to reconsider that position."

"You're not Charles Magnussen, Mr. Holmes. I don't believe that you believe in blackmail as a civilized way of achieving a goal."

He nodded. "You would be correct. Dirty business, really."

Mary stood. "I just wanted to know how much you knew. Just to know."

"Well, now you know."

She held out a manila folder towards him, which Mycroft accepted nonchalantly. He slid the fold open and two pictures dropped into his hands. His face burned suddenly, with annoyance or embarrassment he did not know. "How did you-"

"You're not the only one who knows how to do research, Mycroft," she said with a smile.

Mycroft stood too, his eyes narrowing. "If you think this a threat comparable to what I could do if I so chose-"

"I don't," Mary cut in. "I just thought you should know that your past is traceable too." She glanced down at that photos he was trying hard to cover and her lips quirked. "They're cute. Both of you were. There's nothing wrong with a little baby fat, Mycroft."

"Leave."

She backed away, her hands raised in surrender. "Alright. It was good talking to you. Good to know where we stand." She smiled sincerely. "Thank you."

"Go."

"Alright."

She was almost out the door when Mycroft could no longer resist. "Mary?" She glanced back. "I suppose to would be irresponsible of my not to ask: how, exactly, did you get into my house?"

* * *

 **Did anyone else notice how comfortable Mary and Mycroft were with each other in the Christmas special? (Which I loved, by the way. I don't know about you guys.) You'd think that, what with her shooting his brother and all, he might have been a bit annoyed. And how did she manage to fool him anyway? I figured there must have been a moment when these two met and sorted things out so here it is. I own nothing, but I love reviews.**


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